The bible is written in Aramaic, greek and Hebrew. Any book not in those languages is just a translation of the bible. Translations are not exact, they’re open to interpretation. An example would be idioms. Raining cats and dogs is a common idiom in english but doesn’t translate to other languages with the same meaning. Someone unfamiliar with the idiom could read it to mean animals falling out of the sky, whereas someone familiar with it would read it to mean heavy rain, as intended.

Each church has its own translation of the bible based on someones interpretation of the meaning of the scripts in their original language. The Quran is almost always read in Arabic. That’s why it’s easier for you to see why different groups of christians exist. They’ve codified their interpretations of the bible into a translated book they still call the bible, except it now agrees with their world views.

Muslim countries do the same thing when they make up shariah based laws, except they don’t bother rewriting the Quran every time someone reinterprets the meaning of a part of it. They just say ‘this is what the Quran means by this so this is what the law is’.